Car Feature>> Nismo Z-tune

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Seeing the Z-tune at the recent Nismo Festival I got bombarded with memories from my first drive of the car back when it was unveiled. Since the Z-tune kit entered the scene back in 2005, engine development and additional technology has allowed tuners to continuously fine-tune the second generation of GT-Rs, but the Z-tune will always remain the ultimate BNR34. This is a project that started way back in 2000, with the first ever Nismo Z-tune prototype showing up at the Nismo Festival getting GT-R aficionados very excited. At that time the Z-tune was pretty much a stripped-out race car, packing a 600 HP stroked “Z1″ RB28 that cranked out 478 lb/ft of torque. This initial step was very successful as Nismo beat every other tuned GT-R that participated in the GT-R Tuner Battle, an event that used to be one of the most exciting spectacles of the Nismo Festival.

The following year the project began to evolve and modifications were made to turn the Z-tune into a more street-oriented machine. A new exhaust was developed which incorporated a catalyst to meet ever stringent emission regulations, power was decreased to the 500 HP “Z2″ variant of the engine to make it more durable, while air conditioning and a full Connolly leather interior was added to make it a more comfortable proposition.

As development of the Z2 RB28 continued the engine was even used in the Falken R34 GT-R that competed in the Nürbugring 24h in both 2003 and 2004 where it managed to finish in 5th position behind far more advanced carbon-chassis equipped race cars.

With the engine taken care of Nismo then sent the Z-tune development car over to the Nordschleife where it was put through a demanding chassis and suspension development. Professional drivers were hired to come up with the optimal handling characteristics to make the Z-tune a very unique GT-R to drive. The car was unveiled in 2005 and to further differentiate it from other BNR34s Nismo developed a new front bumper with a far more modern and coherent design and flared front fenders that mimicked the GT-500 GT-Rs. To keep weight down the bumper and fenders were made in dry-carbon just like the R-tune hood, the front diffuser and the rear spoiler.

The car I was invited to sample on the Ashinoko Skyline toll road was Nismo’s own car, the one with the coolest chassis number of them all!

The final Z2 engine is based around the RRR GT-block, which thanks to its thicker cylinder walls guarantees increased durability over the stock or even N1 block. The Z-tune was also the first car to run the Nismo GT plenum, the exact same part that the RB-powered GT-500 GT cars used to run, supplying an equal amount of air to all six cylinders. Special IHI turbos were developed for the Z-tune and fitted on custom manifolds. From the picture above you can also see the bigger diameter Z-tune polished turbine outlet pipes and the special carbon fiber strengthening that was carried out to the suspension turrets, something that was also done to the transmission tunnel. This increased torsional rigidity of the chassis without having to resort to using a roll-cage.

The R-tune hood was fitted with a special intake system, which scooped air from the radiator and forced it into the stock-airbox. Build quality of these composite parts were of the best quality I have ever seen.

The full titanium exhaust system is yet another Z-tune bespoke part and as you can see from this shot, Nismo even fitted transmission and rear differential coolers, each with their own temperature activated electrical pumps. The Z-tune did not run the rear carbon diffuser as found on the V-spec/V-specII/M-spec variants of the BNR34.

Carbon fiber was also used in the trunk to stiffen up the area around the suspension turrets. Behind this part all the electronics of the BNR34 are hidden like the HICAS and ATTESA E-TS Pro ECUs as well as the battery.

The interior was tuned conservatively and brought a little more upmarket thanks to a full red and black leather interior and a more modern alcantara-clad steering wheel.

Out on the road the Z-tune was a true eye-opener. It oozed refinement, you could tell that a lot of time and effort went into guaranteeing every aspect of the car performed flawlessly. The steering, the brakes, the way the engine responded and of course the Sachs suspension all kept a constant stream of information coming through, offering a very rewarding driving experience. The Z2 engine was very responsive but by today’s standard a little laggy with the IHI turbines not offering much below 5,000 rpm. But keep the engine on boil above that magic number and you are rewarded with 1.5 bar of boost, which propels you along on a furious and savage wave of acceleration. The Sachs 3-way racing suspension allow the 1600kg Z-tune to be thrown into corners at physics-defying speeds. Exiting corners is where the fun is with any GT-R as the ATTESA E-TS juggles front/rear power distribution and lets you to exit under hard acceleration with a smidgeon of opposite lock. But things are a bit different in the Z-tune. The ATTESA was reprogrammed to offer much more front end torque transfer as soon as you get on the power, effectively neutralizing any oversteer, something which can be seen in real time on the front-torque gauge on the multi function display unit. This translates to “on-rails” cornering, just throw the car in, get back on power when you think its way too early and it just goes round shooting out of the corner under total control. A bit disappointing for those seeking a more extreme and natural driving technique but undeniably the safest and fastest way to deploy 500HP.

Thanks to the use of a 1.5 way limited slip front differential the steering is heavier off-center weighing up progressively as you wind in lock allowing you to feel precisely what the front tires are up to. Nismo called in Brembo to develop the braking system for the Z-tune which is made up 6-pot front calipers that bite down on 362 mm rotors and 4-pots and 355mm discs at the rear to stabilize things. The ABS system was reprogrammed to take into account the race-car like stopping power, and according to Nismo a maximum of 1.6 G of braking force can be achieved when using semi-slick tires. The pedal feel is weighed and progressive and you have to dose your foot gently because initial pedal bite is very sharp to say the least, which makes heel & toe antics a jerky business at low speeds. The pads are made of a very aggressive compound, which resulted in loud brake squeal but on the other hand provided fade-free performance for two hours straight. This is the brake set-up the BNR34 should have had from the beginning!!

Since I got a lot of requests from people wanting to see more of the Z-tune I will also be posting an additional feature on the assembly of the last Z-tune to have been built. Stay tuned for more Nismo goodness.